Exam questions Flashcards
Which of the following is visible to the naked eye: AV valve Bundle of His left ventricular wall Pulmonary vein Purkyne fibres SA node Semi-lunar valve Septum
AV valve
left ventricular wall
Semi-lunar valve
Septum
Explain why the answer calculated in part (i) may not be an accurate repressentation of the patient’s heart rate and suggest hoe a more accurate answer could be obtained
Only one full cardic cycle shown, so it could be an anomalous
measurement of cycke from different points gives different values
A mean would be better
Digoxin caused the heart rate to change. Identify one other effect of dioxgin
londer T-wave
Explain why phenolphthalein indicator was able to detect the breakdown of triglycerides
The breakdown product is fatty acid. The pH falls as more breakdown occurs
Standard deviation is measures of the spread of results. All significant variables were controlled during the investigation. Identify a limitation of the experiment procedure that caused a high standard deviation and suggest an improvement to the methos that could reduce this spreed of results
limitation: The end point is diffucult to judge
Improvement: USe a pH meter
Tryglycerides contain three elements
C55H98O6 = M C18H30O16 = N
Which of rhw formule coresponds to a triglyceride, and why?
Formula: M
Because: hgih ration of hydrogen and oxygen, approximately 2H : 1O
phospholipid molecules are similar to triglycerides but they also contain the element phosphorus as part of a phosphate group.
Explain how the structure of phospholipids allows them to form the bilayer of a plasma membrane
Hydrophilic head and hydrophobic tail
Hydrophobic tail repelled by water
head forms H-bonds with water
Medium outside and inside the plasma membrane is aqueous
Hydrophobic nature of tail result in their facing towards each other
The plasma membrane also contains proteins, which are made within the cell. Outline the process and the organelles involved in the translation of these proteins fro RNA
(m)RNA transorted out of nucleus
(m)RNA transported to ribosome
Protein synthesis occurs at ribosoe
(t)RNA brings specific amino acids
Peptide bonds form between adjacent amino acids
Polypeptide procesed through Golgi apparatus
After being mixed with iodine, which od the following show a blue/black colour? potato tuber cells erythroctes sieve tube elements neurophils
Potato tuber cells
Which of the folloing is not a role of an intracellular molecule?
cell to cell signalling
partially permeable barrier
site of chemical reactions
transport of substances across the membrane
Cell to cell signalling
Outline how the difference in human size between arteries and veins is related to their functions
In arteries small lumen maintains pressure
In veins low resistance needed because of low pressure
larger cross section compared to circomference means fewer particles ith low resistance
The wall of blood vessels contain a polymer called collagen. Name the type of monomer from which collagen is made and explain how teo such monomers are joined together
Name: Amino acid
Join together by: Peptide bond between amino group and carboxyk group of different amino acid. Water is produced
How have gills adapted for efficient gas exchange?
Many lamella, provides a large SA
Pressure of secondary lamellae on main lamellae provide large SA
Short distance between blood and water. Blood maintains steep consentration gradient
Faster diffusion of oxygen
Each gill is supported by a gill arch made of bone, Bone tissue and gills are describe as organs
A tissue has one type of cells and performs one function
Bone has 1 type of cell
Organs consists of several tissues
Gills contain bone and blood
Explain why it is important for the survival of the llama haemoglobin dissociation curve is the left of the camel haemoglobin dissociation curve
Llama haemoglobin need higher affinity for oxygen so that it can pick up oxygen at lower partial pressure of oxygen
Describe how the structure of llama haemoglobin is likely to be differnt from that of camel haemoglobinwih reference to the four level of protein struture
Difference in primary structure:
difference amino acid
One amino acid change
Amino acid change could cause change to the secondary structure:
initial coiling or folding of polypeptide chain
alpha helix, beta pleated sheat
hydrogen bonds
Amino acid chase cause change in the terry structure: Further coiling of secondary structure ionic bonding, disulphide bonding hydrophobic and hydrophilic bonds 3D shape
Amino acide change does not change quaternary structure:
alpha and beta still able to form haemoglobin in both camel and llama
Three properties of collagen
insoluble
strong
unreactive
A vet is concerned that a llama is unwell. The vet suspects there may be haemoglobin in the urine of the llama. Explain how the vet could confirm this suspicion?
observe colour change from blue to purple
compare wth bank/control urine contain no protein
Explain how pairing of nitrogen bases allows identical copies of DNA to be made
Adenine with thymine and cytosine pairs with guanine
because of hydrogen bonding
purine can only bind with pyrimidine because are different sizes
Outline how the process of DNA replication is completed, following the pairing of nitrogenous bases
DNA polymerase
sugar-phosphate backbone forms between phosphate and sugar
DNA winds into double helix
Why is DNA replication described as semi-conservative?
New molecule consists of 1 old stand and 1 new strand
Which of the following causes the first ‘lub’ component?
Closing of the atrioventricular valves
What can you observe under a light microscope?
Whole cells and tissues
What can you observe under a transmission electron microscope?
Organelles
What can you observe under a laser scanning focal microscope?
An object at a certain depth within a cell
Describe the sequence of organelles involved during the production and secretion of a protein from this cell?
Ribosomes
Golgi apparatus
Lysosome
Plasma membrane
Which of the following formulae of fatty acids represents a saturated fatty acid?
Palmitic acid C15H31COOH
Oleic acid C17H33COOH
Linoleic acid C17H31COOH
Palmitic acid C15H31COOH
Explain why facilitated diffusion via GLUT proteins requires no metabolic energy
Because diffuse occurs when a particle moves from an area of high concentration to an area of low concentration. They move due to their own kinetic energy
Glucose can also be absorbed by an active process which requires metabolic energy. What is the immediate source of this energy in cells?
ATP
Explain why glucose cannot pass through a cell membrane by simple diffusion
Phospholipids act as a barrier
Glucose molecules are too large
The thin stem and thin cell walls do not provide much support for the leaf. Suggest how the leaf is supported
Airspace gives buoyancy
Supported by surrounding water
State what is meant by the resolution of a microsope
It’s how clear the image is. It is the ability to see the separation between two separate points
The slide viewed to draw the diagramhad be stain which stain had the student used? Explain your answer.
Nile blue - nuclei
eosin - cytoplasm
Sudan red - cell membrane
iodine - starch
Nile blue because it increases contrast
What does Nile blue stain?
The nuclei
What does eosin stain?
Cytoplasm
What does Sudan red stain?
Cell membrane
What does iodine stain?
Starch
What stain would you use to highlight the nuclei?
Nile blue
What stain would you use to highlight the cytoplasm?
Eosin
What stain would you use to highlight the cell membrane?
Sudan red
What stain would you use to highlight the starch?
iodine
Which 2 molecules make up triglyceride?
Glycerol and fatty acids
A triglyceride has three of which bond?
Ester bond
Why are animal lipids more dense than plant lipids?
Because they are less saturated
What molecule is liberated when fatty acids bond to glycerol?
Ester bonds form with a condensation reaction, liberating a molecule of water with each bond
What do we call molecules which are non-polar and therefore do not dissolve in water?
Hydrophobic - triglycerides are hydrophobic, so do not mix well with water
What is the difference between phospholipids and triglycerides
Phospholipids have a phosphate group in place of one fatty acid
What do we call the build up of cholesterol in the walls of arteries?
Atherosclerosis
Which chemical group is not found on an amino acid? (give an example)
Phosphate group
Which is the correct formula for an amino group?
NH3
What do we call a fatty acid where all of the carbon-carbon bonds are single?
Saturated
What type of bond does water form with other water molecules
Hydrogen bonds, which are weak interaction between the slightly negative oxygen atom on one molecule and the slightly positive hydrogen atom on another molecule
What do we call molecules, like water, that have a slightly negative end and slightly positive end?
Polar
What do we call the energy that is removed when water evapourate?
Latent heat of vaporization - water has relatively high latent heat of vapourisation
What is unusual about what happens to water as it freezes?
It becomes less dense - below about 4oC, water molecule spread out as it creates a crystalline form
What do we call the energy requided to raise 1 gram of substance by 1oC?
Specific heat capacity - water has a relatively high specific heat capacity, making it thermally stable
How can pond skater stand on water?
Water has surface tension
Why is it important to life that ice floats?
It insulates the water below, the insulation helps to keep the water below it in liquid form
What is it called when water molecule stick together?
Cohesion - whilst the H-bond cause surface tension, all fo the molecules will be held together by cohesion
IS water a good solvent?
Yes, anything ionic or polar will dissolve in water
Why is it useful that water is transparent?
It enables aquatic plant to photosynthesis
Glycogen is mode from which monomer?
Alpha glucose
Which polysaccharide is formed from 1-4 and 1-6 glycosidic bonds?
Amylopectin
Which polysaccharide is formed from alpha glucose molecules joined by 1-4 glycosidic bonds only?
Amylose
Which storage molecule is more energy dense glycogen or starch?
glycogen - whilst both molecules are energy dense, glycogen is more compact
Which bonds exist between microfibrils in cellulose?
Hydrogen bonds
What links the polysaccharide chains in bacterial peptidoglycan cell walls?
Peptide cross-links-short sections of amino acids form peptide cross-links between the long chains
Chitin forms in the fungal cell wall, where else can it be found?
In the shells of insects and crustaceans
Why is it important to plants and animals that starch and glycogen are insoluble?
Any soluble substance will lower the water potential of its solution, thus triggering water movement by osmosis - so they don’t affect water potential
What is the difference between glycogen and starch?
Whilst both polysaccharides have 1-4 and 1-6 glycosidic bonds, glycogen branches more frequently 1-6bonds
Which chemical group is present in chitin, but not cellulose?
Acetylamino
